1. Field of the Invention
The present invention relates to an integrated coking and hydroconversion process for upgrading carbonaceous materials.
2. Description of the Prior Art
Coking is a well-known process. The fluid coking process is described, for example, in U.S. Pat. No. 2,881,130, the teachings of which are hereby incorporated by reference. The fluid coking process can be conducted with or without recycle of the heavy normally liquid constituents of the coking product. When the heavy normally liquid constituents of the coker product are not recycled to the coking zone, the process is referred to as "once-through" coking. Integrated fluid coking and coke gasification processes are also known and disclosed, for example, in U.S. Pat. Nos. 3,702,516; 3,759,676, and 4,325,815, the teachings of which are hereby incorporated by reference. Delayed coking is a well-known process in which a hydrocarbonaceous oil is heated to a cracking temperature and then passed into a coking drum to produce a vapor phase product, including hydrocarbons and coke. The drum is decoked by hydraulic or by mechanical means. See Hydrocarbon Processing, September 1980, page 153.
U.S. Pat. No. 4,134,825 discloses a catalytic slurry hydroconversion process conducted at a pressure of 500 to 5000 psig and at elevated temperatures. The catalyst is produced in the oil feed from a catalyst precursor.
The term "hydroconversion" is used herein to designate a process conducted in the presence of hydrogen in which at least a portion of the heavy constituents of a hydrocarbonaceous oil is converted to lower boiling products while simultaneously reducing the concentration of nitrogenous compounds, sulphur compounds and metallic contaminants.
U.S. Pat. No. 3,684,689 discloses fluid coking a residuum at a pressure above 150 psig. The coker bottoms are passed to a hydrocracking zone. The stream passed to the hydrocracking zone is a gas oil (see column 3, line 74 and column 6, lines 72-73).
U.S. Pat. No. 2,614,067 discloses coking a topped crude oil in a fluid coker. A gas oil fraction from a fractionator is used as absorber oil in an absorber. The absorber bottoms are passed to a slurry hydrogenation reactor. The absorber bottoms do not seem to include constituents boiling above 1050.degree. F.
U.S. Pat. No. 3,245,900 discloses coking a residuum and sending the coker distillate to a hydrocracking zone.
U.S. Pat. No. 2,888,393 discloses fluid coking at a pressure of 200 to 2000 psig and hydrogenating the entire coker effluent at a pressure ranging from 200 to 2000 psig.
U.S. Pat. Nos. 4,204,943; 4,178,227, and 4,169,038 disclose combination hydroconversion and coking in which the bottoms portion of the hydroconverted product is used as feed to the coking zone.
It has now been found that an integrated coking and hydroconversion process in which the coker bottoms, including materials boiling above 1050.degree. F., are further converted in a catalytic slurry hydroconversion stage, will provide advantages that will become apparent in the ensuing description.
All boiling points referred to herein are atmospheric pressure equivalent boiling points unless otherwise specified.